Methods of making a particle having an attached stable free radical

ABSTRACT

A modified particle is disclosed wherein a particle has an attached group having the formula:                    
     wherein Ar represents an aromatic group; R 1  represents a bond, an arylene group, an alkylene group,                    
     wherein R 4  is an alkyl or alkylene group or an aryl or arylene group; R 2  and R 3 , which can be the same or different, represent hydrogen, an alkyl group, an aryl group, —OR 5 , —NHR 5 , —NR 5 R 5 , or —SR 5 , wherein R 5 , which is the same or different, represents an alkyl group or an aryl group; and SFR represents a stable free radical. Also disclosed is a modified particle or aggregate having attached a group having the formula:                    
     wherein CoupA represents a Si-containing group, a Ti-containing group, or a Zr-containing group; R 8  and R 9 , which can be the same or different, represent hydrogen, an alkyl group, an aryl group, —OR 10 , —NHR 10 , —NR 10 R 10 , or —SR 10 , wherein R 10  represents an alkyl group or an aryl group; SFR represents a stable free radical; and n is an integer of from 1 to 3. A modified particle having an attached —SFR or —X—SFR is additionally disclosed. Also, modified particles with attached polymers are also disclosed as well as methods of making the modified particles.

BACKGROUND OF THE INVENTION

The present invention relates to particles, such as carbon black, havingan attached stable free radical which permits the formation of blockedradical sources. The present invention further relates to methods ofpreparing and using such modified particles.

The role of carbon black as a thermal stabilizer in polymeric systems isdiscussed by W. L. Hawkins, R. H. Hansen, W. Matreyek, F. H. Winslow; J.Applied Polymer Science, vol. 1, pages 37-42, 1959; J. T. Cruver, K. W.Rollmann: J. Applied Polymer Science, vol. 8, pages 1169-83, 1964, andby G. Ivan, M. Giurgina: Revue Roumaine de Chemie, vol. 29, number 8,pages 639-646, 1984. In each discussion the mechanism is throughphenolic and quinone oxygen groups on the carbon black surface behavingeither as radical traps or peroxide decomposers. One skilled in the art,however, would consider these sites unavailable as initiating sites forpolymerization processes.

Belmont et al. (J. A. Belmont, J. M. Funt: International RubberConference, Essen, Germany, Jun. 24-27 1991) identified the presence ofperoxide groups, typically in the range of 0.1 to 0.4 micromoles/sqmeter, on the carbon black surface. However, the majority (greater than80%) of the peroxide groups are thermally stable to heat treatment at200° C. and hence cannot be considered to be potential initiating sitesfor radical polymerization.

Tsubokawa et al. (K. Fujiki, N. Tsubokawa, Y. Sone: Polymer J., vol. 22,number 8, pages 661-70, 1990, and N. Tsubokawa: Prog. Polymer Science,vol. 17, pages 417-70, 1992) discuss growing polymers from an activatedcarbon black surface by first attaching a reactive group via the oxygengroups on the carbon black surface. Typical examples include the use ofglycidyl methacrylate where the glycidyl group reacts with phenolichydroxyl groups on the carbon black surface providing a vinylfunctionality; the reaction of 4,4′ azo bis-(4-cyanovaleric acid)whereby the isocyanate group reacts with phenolic hydroxyl groups andsubsequent heating decomposes the azo group to generate an alkylradical; and the reaction of the phenolic hydroxyl groups with butyllithium which can then be used as an initiation site for anionicpolymerization.

All of these approaches require the presence of oxygen groups on thecarbon black surface. Since the level of reactive hydroxyl andcarboxylic acid groups, relative to the above approaches, present on atypical furnace or thermal carbon black is typically 0.01 to 0.1micromoles/sq meter, the number of potential initiation sites is quitelow.

Further, subsequent polymerization from these activated sites will mostlikely occur in the normal manner for free radical polymerization withthe chains being irreversible terminated by chain combination reactions,combination with unreacted oxygen groups on the carbon black surface,and/or the addition of chain stoppers. In all cases the polymerizationcannot be reinitiated. Accordingly, there is a need to provide particleswith attached stable free radicals which overcome the above-describedlimitations.

SUMMARY OF THE INVENTION

In accordance with the purpose of the present invention, the presentinvention relates to a modified particle which includes a particlehaving an attached group having the formula:

wherein Ar represents an aromatic group; R¹ represents a bond, anarylene group, an alkylene group,

wherein R⁴ is an alkyl or alkylene group or an aryl or arylene group; R²and R³, which can be the same or different, represent hydrogen, an alkylgroup, an aryl group, —OR⁵, —NHR⁵, —NR⁵R⁵ or —SR⁵, wherein R⁵, which canbe the same or different, represents hydrogen, an alkyl group or an arylgroup; and SFR represents a stable free radical.

The present invention further relates to a modified particle oraggregate wherein the particle or aggregate is a carbon-metal multiphaseaggregate, a carbon-silicon containing species multiphase aggregate, ametal oxide, or a metal hydroxide. Attached to the particle or aggregateis a group having the formula:

wherein CoupA represents a Si-containing group, a Ti-containing group,or a Zr-containing group; R⁸ and R⁹, which can be the same or different,represent hydrogen, an alkyl group, an aryl group, —OR¹⁰, —NHR¹⁰,—NR¹⁰R¹⁰, or —SR¹⁰, wherein R¹⁰, which can be the same or different,represents hydrogen, an alkyl group or an aryl group; SFR represents astable free radical, and n is an integer of from 1 to 3.

The present invention further relates to a modified particle with anattached polymer wherein the modified particle has an attached grouphaving the formula:

wherein X represents a polymer formed from at least one polymerizablevinyl or diene based monomer, Ar represents an aromatic group; R¹represents a bond, an arylene group, an alkylene group,

wherein R⁴ is an alkyl or alkylene group or an aryl or arylene group; R²and R³, which can be the same or different, represent hydrogen, an alkylgroup, an aryl group, —OR⁵, —NHR⁵, —NR⁵R⁵ or —SR⁵, wherein R⁵, which canbe the same or different, represents an alkyl group or an aryl group;and SFR represents a stable free radical.

The present invention also relates to another modified particle havingan attached polymer. The particle is a carbon-metal phase aggregate, acarbon-silicon containing species phase aggregate, a metal oxide, or ametal hydroxide. Attached to the particle is a group having the formula:

wherein CoupA represents a Si-containing group, a Ti-containing group,or a Zr-containing group; R⁸ and R⁹, which can be the same or different,represent hydrogen, an alkyl group, an aryl group, —OR¹⁰, —NHR¹⁰,—NR¹⁰R¹⁰, or —SR¹⁰, wherein R¹⁰, which can be the same or different,represents an alkyl group or an aryl group; SFR represents a stable freeradical, X is a polymer formed from at least one polymerizable monomer,and n is an integer of from 1 to 3.

The present invention, in addition, relates to a method for preparingand using these various modified particles. The method includes reactinga particle having an attached vinyl substituted aromatic group with areactive free radical source and a stable free radical source to form areaction product. The present application further relates to forming themodified particles with an attached polymer by reacting the reactionproduct with a polymerizable monomer.

The present invention further relates to a method of making a modifiedparticle comprising a particle having attached a group having theformula:

wherein Ar represents an aromatic group; R¹ represents a bond, anarylene group, an alkylene group,

wherein R⁴ is an alkyl or alkylene group or an aryl or arylene group; R²and R³, which can be the same or different, represent hydrogen, an alkylgroup, an aryl group, —OR⁵, —NHR⁵, —NR⁵R⁵, or —SR⁵, wherein R⁵, which isthe same or different, represents an alkyl group or an aryl group; andSFR represents a stable free radical, wherein said method comprisesreacting a) a particle having attached an aromatic group with a groupcontaining an abstractable proton and which leaves behind acarbon-centered radical when the proton is abstracted with b) a reactivefree radical source and c) a stable free radical source.

The present invention, in addition, relates to a modified particle whichincludes a particle having an organic group having a —SFR group, wherethe organic group is directly attached to the particle. The modifiedparticle can also be a particle having an organic group having an —X—SFRgroup, where the organic group is directly attached to the particle.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are intended to provide further explanation of the presentinvention, as claimed.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

In one embodiment, the present invention relates to a modified particlecomprising a particle having attached a group having the formula:

wherein Ar represents an aromatic group which is attached to theparticle; R¹ represents a bond, an arylene group, an alkylene group,

wherein R⁴ is an alkyl or alkylene group or an aryl or arylene group; R²and R³, which can be the same or different, represent hydrogen, an alkylgroup, an aryl group, —OR⁵, —NHR⁵, —NR⁵R⁵, or —SR⁵, wherein R⁵, whichcan be the same or different, represents an alkyl group or an arylgroup; and SFR represents a stable free radical.

The particle, to be modified, can be any particle capable of having agroup represented by any one of formulas described herein attachedthereto, such as formula (I)-(IV). Preferably, the particle has a carbonreactive site (C—), since in a preferred embodiment for the groups offormula (I) and (III), —SFR and —X—SFR are preferably attached through acarbon bond on the particle. The particle, for instance, can be carbonproducts, metal oxides (e.g., silica), metal hydroxides, multiphaseaggregates comprising a carbon phase and a silicon-containing speciesphase, multiphase aggregates comprising a carbon phase and ametal-containing species phase, and the like. The carbon may be of thecrystalline and/or amorphous type. Examples of carbon products includebut are not limited to, graphite, -carbon black, vitreous carbon,activated charcoal, activated carbon, carbon fiber, and mixturesthereof. Finely divided forms of the above are preferred. Mostpreferably, the particle is a carbon product, and most preferably carbonblack.

The multiphase aggregate containing the carbon phase and thesilicon-containing species phase can also be considered asilicon-treated carbon black aggregate and the multiphase aggregatecontaining a carbon phase and a metal-containing species phase can beconsidered to be a metal-treated carbon black aggregate as long as onerealizes that in either case, the silicon-containing species and/ormetal-containing species are a phase of the aggregate just like thecarbon phase. The multiphase aggregates do not represent a mixture ofdiscrete carbon black aggregates and discrete silica or metal aggregatesand is not a silica coated carbon black. Rather, the multiphaseaggregates used in the present invention include at least onesilicon-containing or metal-containing region concentrated at or nearthe surface of the aggregate (but put of the aggregate) and/or withinthe aggregate.

The aggregate, thus contains at least two phases, one of which is carbonand the other of which is a silicon-containing species, ametal-containing species, or both. The silicon-containing species thatcan be a part of the aggregate is not attached to a carbon blackaggregate like a silica coupling agent, but actually is part of the sameaggregate as the carbon phase. For instance, when the multiphaseaggregate having a carbon phase and a silicon-containing species phaseis examined under STEM-EDX, the silicon signal corresponding to thesilicon-containing species is found to be present in individual carbonblack aggregates. By comparison, for example, in a physical mixture ofsilica and carbon black, STEM-EDX examination reveals distinctlyseparate silica and carbon black aggregates.

The metal-treated carbon blacks are aggregates containing at least acarbon phase and a metal-containing species phase. The metal-containingspecies include compounds containing aluminum, zinc, magnesium, calcium,titanium, vandium, cobalt, nickel, zirconium, tin, antimony, chromium,neodymium, lead, tellurium, barium, cesium, iron, and molybdenum.Preferably, the metal-containing species phase is an aluminum- orzinc-containing species phase. The metal-containing species phase can bedistributed through at least a portion of the aggregate and is anintrinsic part of the aggregate.

Further, it is within the bounds of the present invention to have ametal-treated carbon black containing more than one type ofmetal-containing species phase or the metal-treated carbon black canalso contain a silicon-containing species phase and/or aboron-containing species phase. For example, the metal-treated carbonblack of the present invention can have an aggregate comprising a carbonphase, an aluminum-containing species phase, and a zinc-containingspecies phase. Accordingly, the multiphase aggregates used in thepresent invention can have two or more different types ofmetal-containing species phases and/or additional non-metal speciesphases.

Preferably, for purposes of the present invention, the amount ofelemental silicon and/or elemental metal present in the multiphaseaggregate is from about 0.1 to about 25 wt. %, more preferably, fromabout 0.5 wt. % to about 10 wt. %, and most preferably from about 0.2wt. % to about 5.4 wt. %, by weight of the aggregate.

The details of making the multiphase aggregates are explained in U.S.patent application Ser. Nos.: 08/446,141, filed May 22, 1995 U.S. Pat.No. 5,830,930; 08/446,142, filed May 22, 1995 U.S. Pat. No. 5,877,238;08/528,895, filed Sep. 15, 1995 abandoned; and 08/750,017, filed Nov.22, 1996, which is a National Phase Application of PCT No. WO 96/37547,filed May 21, 1996, U.S. patent application Ser. No. 08/828,785, filedMar. 27, 1997 U.S. Pat. No. 6,017,980, U.S. patent application Nos.08/837,493 filed Apr. 18, 1997 U.S. Pat. No. 5,904,762 and 09/061,871filed Apr. 17, 1998 U.S. Pat. No. 6,057,387. All of these patentapplications are hereby incorporated in their entireties herein byreference.

A silica-coated carbon product can also be used as the particle, such asthat described in PCT Application No. WO 96/37547, published November28, 1996, which is hereby incorporated in its entirety herein byreference.

Particles useful for the present invention may, for example, haveprimary particles sizes in the general range of from about 10 nm toabout 500 nm, and preferably from about 10 nm to about 250 nm, andprimary aggregate sizes in the general range of from about 50 nm toabout 100 microns, preferably from about 50 nm to about 10 microns,still more preferably from about 75 nm to about 1 micron. The BETsurface area of these particles can be any suitable surface area andpreferably ranges from about 10 m²/g to about 2000 m²/g and morepreferably, from about 10 m²/g to about 1,000 m²/g, and still morepreferably from about 50 m²/g to about 500 m²/g; and the particlestructure preferably ranges from about 10 cc/100 g to about 1000 cc/g,more preferably, from about 50 cc/100 g to about 200cc/100 g.

The number of SFR groups directly attached to the particle prior topolymerization can be any amount. For instance, the number of —SFRgroups may range from about 0.01 mmole/g (of particle) to about 10mmole/g, or from about 0.1 mmole/g to about 4 mmole/g, or from about0.05 mmole/g to 4 mmole/g or from about 0.5 mmole/g to about 3 mmole/g,or from about 0.1 mmole/g to about 2 mmole/g.

When the particle is a multiphase aggregate, like a particle comprisinga carbon phase and a silicon-containing species phase, preferably thegroup of formula (I) or (III) is attached at least, if not exclusively,on the carbon phase.

With regard to the aromatic group (Ar), any aromatic group may be used.Unlike the polymerizable monomer discussed later, the aromatic group isnot a polymer and is not polymerized. Examples include, but are notlimited to, arylene groups. Preferred arylene groups include, but arenot limited to, phenylene and naphthalene groups.

With respect to R¹, preferred arylene groups include, but are notlimited to, benzene ring containing groups. Preferred alkylene groupsinclude, but are not limited to, C₁-C₁₈ alkylene-containing groups.These groups can be linear, branched, or unsaturated. These examples ofarylene and alkylene groups can also be considered examples of R⁴.Preferred alkyl groups for R⁴ are C₁-C₂₀ alkyl groups, more preferablyC₁-C₅ alkyl groups and preferred aryl groups are phenyl, biphenyl, andnaphthyl.

With respect to R² and R³, which can be the same or different, examplesof alkyl groups (e.g. C₁-C₂₀ alkyl group) include, but are not limitedto, methyl,. ethyl, propyl, butyl, and the like. Preferably, the alkylgroup is a C₁-C₅ alkyl group. Examples of aryl groups include but arenot limited to phenyl, biphenyl, and naphthyl. The alkyl and aryl groupsmentioned here as well as the arylene and alkylene groups mentionedthroughout can be unsubstituted or substituted for purposes of thepresent invention. R⁵ can be the same type of alkyl and aryl groupsmentioned above with respect to R² and R³.

SFR, which is the stable free radical, can be any radical capable ofcapping the remaining portion of the group attached onto the particle.Examples of the SFR include, but are not limited to, nitroxide freeradicals such as 2,2,5,5-tetramethyl-pyrrolidinyloxy and2,2,6,6-tetramethyl-piperindinyloxy, organic hydrazyl compounds, organicverdazyl compounds, organic aroxyl compounds (e.g., 2,4,6 tri-tertiarybutyl phenoxy radical, galvinoxyl (2,6 ditertiary butyl alpha 3,5ditertiary butyl oxo 2,5 cyclohexadiene-1 ylidene para tolyoxy)radical), aryl alkyl or aryl cycloalkyl where the unpaired electron ison a carbon atom, substituted triphenyl methyl, substituted triphenylamine, and derivatives of these compounds.

The SFR used in the present invention preferably has the formulas:

wherein R⁶ and R⁷, which can be the same or different, represent asubstituted or unsubstituted alkyl or cycloalkyl group; and Ar²represents a substituted or unsubstituted aromatic group. Representativeexamples of the alkyl and aromatic groups can be the same as describedabove with respect to the substitutents R² and R³.

Another embodiment of the present invention relates to a modifiedparticle or aggregate having a group of formula (II) attached thereto.The particle can be a metal oxide, a metal hydroxide, an aggregatecomprising a carbon phase and a metal-containing species phase, or anaggregate comprising a carbon phase and a silicon-containing speciesphase. Attached to this particle or aggregate is a group having theformula:

wherein CoupA represents a Si-containing group, a Ti-containing group,or a Zr-containing group; R⁸ and R⁹, which can be the same or different,represent hydrogen, an alkyl group, an aryl group, —OR¹⁰, —NHR¹⁰,—NR¹⁰R¹⁰, or —SR¹⁰, wherein R¹⁰ represents an alkyl group or an arylgroup; SFR represents a stable free radical, and where n is an integerof from 1 to 3. Preferably, CoupA is attached to the particle oraggregate, especially in the case of a Si-containing group, via anoxygen radical which can form a part of a CoupA.

Examples of Si-containing groups include, but are not limited to,dimethylsilylmethyl, dialkoxysilylmethyl, and the like. Examples ofTi-containing groups include, but are not limited to, alpha substitutedtri-acetyl titanate and the like. Examples of Zr-containing groupsinclude, but are not limited to, dialpha methoxy neopentylzirconate andthe like.

Examples of the substituents R⁸ and R⁹ can be the same as thesubstituents R² and R³ mentioned above. Likewise, examples of thesubstituent R¹⁰ can be the same as the substituent R⁵ discussed above.Also, the SFR is the same as discussed above.

The modified particles having the attached group of the formulas, suchas formula (I), can be made in the following manner. A particle, such ascarbon black, can first have a vinyl substituted aromatic group attachedto the particle. This attachment can be accomplished by the methodsdescribed in PCT International Application No. WO 96/18688 and U.S. Pat.Nos. 5,630,868; 5,559,169; 5,571,311; and 5,559,169 as well as U.S.patent application Ser. No. 08,572,525, U.S. Pat. No. 5,764,677 all ofwhich are hereby incorporated in their entireties by reference herein.

The particle having the attached vinyl substituted aromatic group isthen reacted with a reactive free radical source and a stable freeradical source for a sufficient time and at a sufficient temperature toform the modified particle having the attached group, like that offormula I. The molar ratio of the reactive free radical source to thestable free radical source is from about 0.7 to about 2.0, andpreferably from about 0.9 to about 1.1. Examples of the reactive freeradical source include but are not limited to radicals generated fromorganic peroxides such as benzoyl peroxides and azo initiators such asazobisisobutyronitrile, and the like. The reactive free radical sourceis present in amounts sufficient to react with the vinyl aromatic grouppresent on the particle. Preferably, the amount of the reactive radicalsource is from about 0.01 mmoles/g (of particle) to about 10 mmoles/gand more preferably from about 0.01 to about 5 mmoles/g.

Alternatively, the modified particles of the present invention can bemade by first forming the groups of the formulas described above, suchas formula (I). Preferably, the stable free radical group is attached inthe meta or para position of the aromatic group. This group is thenattached to the particle by a diazonium treatment in the mannerdescribed in the above referenced patents and patent applications, wherea diazonium salt will first be formed containing a group of one of theformulas described above in the manner described in the above-referencedpatents. The groups of the formulas can be then subsequently attached tothe particle. In a less preferred way, the formulas of the presentinvention can be attached to the particle through a hydroxyl or carbonylgroup present on the particle. Also, the modified particle of thepresent invention can be formed by attaching a stable free radicalcompound containing at least one alkoxy silyl, alkoxy titanyl, or alkoxyzirconyl group to the particle which, in this particular process ispreferably a metal oxide or metal hydroxide, or a carbon surface. Thisparticular embodiment would attach. a group of formula (II) or (IV) to aparticle.

In another process, the modified particle can be formed by first takingan aromatic group and reacting it with a compound to form the groups ofthe formulas described above except for the presence of the —SFR group.In other words, a group having the formula Ar—R¹—CR²R³ would first beformed and then the —SFR would be attached to this group to form a groupof formula (I) of the present invention which can then be attached tothe particle. In this process, R² and R³ are preferably hydrogen.

A related process involves first taking an aromatic group, such as agroup having the formula Ar—R¹—CR²R³ and attaching it onto the particle,for instance by a diazonium treatment in a manner described above, andthen attaching the —SFR group to form a group of formula (1) of thepresent invention. Example 7 of the present application shows a specificembodiment of this process. In more detail, this process involves protonabstraction wherein a group containing an abstractable proton whichleaves behind a carbon-centered radical is attached onto an aromaticgroup, wherein the aromatic group is directly attached to the particle.For purposes of this process, the aromatic group can first be attachedto the particle and then subsequently a group containing theabstractable proton can then be attached or an aromatic group containingan abstractable proton can be attached onto the particle, for instance,by a diazonium treatment as described above. Then, a reactive freeradical source and a stable free radical source are reacted with theparticle having the attached aromatic group with the group containing anabstractable proton for a sufficient time and at a sufficienttemperature to form the modified particle having the attached group,like that of formula (I). This modified particle having the attachedgroup, like that of formula (I) can then be subjected to polymerizationreactions in order to have polymers attached thereto such as set forthin formula (III). In this process, the reactive free radical sourceabstracts the proton from the group containing the abstractable protonwhich thus leaves a carbon-centered radical behind which permits thestable free radical source to attached thereto to create the modifiedparticles of the present invention such as set forth in formula (I).Examples of a group containing an abstractable proton which leavesbehind a carbon-centered radical include alkyl groups, alkenes with ahydrogen atom in the alpha position to the olefinic bond, and the like.Specific examples include C₁-C₂₀ alkyl groups, such as methyl, ethyl,propyl, butyl, and the like. The reactive free radical source for thisprocess can be organic peroxides such as benzoyl peroxides and t-butylperoxides. Examples of the stable free radical source are describedabove and can be the same for this process. This process can also beapplied where the modified particle aggregate has a group attached likethat of formula (II) and (IV).

Alternatively, the process of making the modified particles of thepresent invention can be a three step process where Ar is first attachedto the particle and then the group having the formula R¹—C—R²R³ can beattached to the aromatic group. Then in a third step, the —SFR can beattached to the R¹—C—R²R³ group.

Also, in making the modified particles having the attached group of onethe formulas described above, an aliphatic vinyl group can be attachedto the particle surface by a diazotisation of a vinyl substituted aminoaromatic compound, or a vinyl substituted alkoxy silyl, titanyl, orzirconyl derivative. The vinyl group is then reacted with an organicperoxide and a stable free radical such that the organic peroxide andstable free radical are present in an amount sufficient to react with atleast one percent of the vinyl groups and preferably from about 50 toabout 100% of the vinyl groups and the mole ratios of the organicperoxide to stable free radical are preferably from about 0.5:1 to about1:1.

The modified particles of formula (II) can be made in the followingmanner. The aggregate comprising a carbon phase and a metal-containingspecies phase can be made as described in U.S. patent application Ser.No. 8/828,725, U.S. Pat. No. 5,752,773 hereby incorporated herein byreference. The aggregate comprising a carbon phase and a metalcontaining species phase can be made as described in U.S. patentapplication Ser. No. 08/446,141 and 08/750,017. The aggregate orparticle can then be reacted with a coupling agent by adding thecoupling agent to the aggregate in a medium and mixing. Then, theaggregate or particle having the attached coupling group can be reactedwith a reactive radical source and stable free radical source asdescribed above.

For purposes of the above-described reactions, the reaction should occurfor a time and temperature sufficient to form the attached group ontothe particle or aggregate. Generally, this time is from about 3 minutesto about 96 hours and more preferably from about 1 hour to about 24hours. The temperature of the reaction is dependent on the half-life ofthe peroxide, preferably from about 50° C. to about 200° C., and morepreferably from about 75° C. to about 125° C.

With the modified particles described above, polymers can be attachedonto these attached groups by reacting these modified particles oraggregates with a polymerizable monomer such as a vinyl or dienecontaining monomer. Specific examples of such monomers include, but arenot limited to styrene, isoprene, butadiene, chloromethylstyrene, methylmethacrylate, and butyl methacrylate, as well as acrylic acid and estersof acrylic acid and methacrylic acid and esters of methacrylic acid.Mixtures of two or more monomers can be also used and/or polymerizedsequentially.

The polymerization reaction is conducted under conditions which permitsthe polymerization of the monomer so that it forms a part of the groupattached onto the particle or aggregate. These conditions are preferablyheating modified particles with a monomer above 80° C., preferably fromabout 120° C. to about 150° C., optionally in the presence of a solvent.The reaction can be ended by lowering the temperature below 80° C. Thepolymer-modified particle can then be subjected to distillation, steamstripping, or precipitation or other known methods in order to removeresidual monomers and solvents.

The polymerization reaction thus can produce any length of polymer onthe modified particle or aggregate. For example, polymers having averagemolecular weights, preferably ranging from about 1,000 to about1,000,000 can be made. The polymers can be any type, such ashomopolymers, co-polymers, ter-polymers, or higher chain polymers. Thepolymers can also be block, graft, or random-type polymers.

Once the polymerization occurs, the modified particle will have a groupattached having the formula:

wherein the substituents are the same as described earlier for formula(I) and X is a polymer formed from at least one polymerizable monomer.

Similarly, when the modified particle or aggregate having a group offormula (II) is polymerized by the introduction of one or more monomers,the group attached to the particle or aggregate will have the formula:

wherein the substituents are the same as described in formula (II) and Xis a polymer formed from at least one polymerizable monomer.

In another embodiment, a modified particle has an organic groupcontaining a —SFR group directly attached to the particle. Preferably,the —SFR group is directly attached to the particle. The —SFR group andparticle can be the same as discussed above. This type of modifiedparticle can be prepared by heating a particle, like carbon black, witha organic group comprising a stable free radical in a solvent, such astoluene and preferably, in an inert atmosphere. With this modifiedparticle having an attached organic group having a —SFR group, polymerscan be attached onto the —SFR group by reacting the modified particlewith a polymerizable monomer as discussed above using the sameprocedure.

With any of the above-described groups containing the —SFR group, themodified particle or aggregate containing the —SFR group can beterminated by any means known to those skilled in the art in view of thepresent application. In particular, the —SFR group can be replaced witha proton, subjected to disproportionation, or replaced with a chemicalgroup through group transfer and the like. For instance, the —SFR groupcan be replaced with a hydroxy or halide group, or other terminatinggroup known to those skilled in the art. This termination of removingthe —SFR group and replacing it or terminating it with another group canbe accomplished, for instance, by methods described in 214 ASC Nat'lMtg, Las Vegas, Sep. 7-11, 1997, Paper in ORGN O61, Gravert, D. J.;Datta A.; Wentworth P., Jr.; Janda, K. D., which are incorporated intheir entirety by reference herein.

The modified particles of the present invention can form part of apolymeric composition and be present with other ingredients commonlyused and found in polymeric compositions.

The modified particle of the present invention can be used in a varietyof applications. For instance, it can be used in coating or inkcompositions, such as printing inks and ink jet inks, toners, automobilecoatings, and the like. Also, the modified particles can be used asreinforcers for compositions, such as polymeric compositions and canalso serve as impact modifiers, or as agents used to increasecompatibility of a polymeric composition.

In more detail, reinforcement of elastomeric compositions includingtire, hose, profile extrusion, seals, gaskets, and vibration isolationunits, as well as the specific reinforcement of a single elastomer phasein a multiphase elastomer blend composition; reinforcement ofthermoplastic compositions such as polyolefines, styrenic, acrylics,polyesters and polyamides, and thermoplastic elastomers andthermoplastic polyolefines; reinforcement of thermoset compositions,e.g., acrylics; impact modification of thermoplastic compositions;impact modification of thermosets; highly dispersible masterbatch forpigmentation, reinforcement, and/or UV protection of thermoplasticcompositions, coatings, thermoplastic elastomers, and crosslinkedcompositions; as a synthetic support for solid phase organic synthesis;as a support or medium for effluent extraction processes both organicand inorganic components; as a catalyst support; and/or as asuperadsorbant for either aqueous of hydrocarbon materials e.g., use insanitary wear, growing medium for plants.

The present invention will be further clarified by the followingexamples, which are intended to be purely exemplary of the invention.

EXAMPLES Example 1

Attachment of 2,2,6,6 tetramethyl piperidinyloxy free radical (TEMPO) tocarbon black.

TEMPO and carbon black grade Vulcan 7H® were added to toluene and heatedunder an inert atmosphere at 130° C. for 96 hours. The carbon black wasfiltered from the toluene, washed with deionized water, and dried.

Kjeld analysis of the resultant carbon black indicated that the nitrogencontent of the carbon black had increased from 0.040% to 0.57% byweight. This equates to 0.09 micromoles of TEMPO attachment per sq meterof carbon black surface area.

Comparing this example with attachment of sulfonic acid via adiazotization process, this equates to about 3% of surface coverage.

Example 2

The TEMPO modified carbon black prepared in Example 1 was combined withfreshly distilled styrene and heated for various time intervalsindicated in the Table under an inert argon atmosphere.

After completion of the specific time interval, the reaction wasterminated by removing the heat source. The treated carbon black sampleswere filtered and extracted under Soxhlet refluxing condition withtetrahydrofuran for 48 hours.

Analysis of the treated carbon black samples for organic content wascarried out using TGA analysis and heating rate of 200 C/minute under anitrogen flow rate of 50 ml/minute.

organic content Temperature (° C.) Time (hours) (% by weight of carbonblack) 125 16 1.12% 150 16 2.46% 130 72 16.5%

Example 3

Vinyl benzene functionalized carbon black prepared by the diazotizationof amino styrene (using the procedure in U.S. Pat. No. 5,571,311) wasreacted with benzoyl peroxide and TEMPO for 16 hours at 70° C. under anargon atmosphere. The resultant carbon black was extracted withtetrahydrofuran and submitted for nitrogen analysis using the Kjeldtechnique, which indicates 2 micromoles of TEMPO attachment per sq.meter of carbon black surface area.

Example 4

The modified carbon black described in Example 3 was heated with styreneunder an inert argon atmosphere for 72 hours at 130° C. The reactedcarbon black was extracted with tetrahydrofuran under Soxhlet refluxconditions for 48 hours to remove any unattached polystyrene. TGAanalysis indicated that the reacted carbon black contained 35 % (byweight of carbon black) organic material.

Example 5 (Comparative)

Using the procedure described by Georges in Macromolecules, vol. 26,pages 2987-8, (1993), a TEMPO terminated polystyrene was produced with amolecular weight, determined by GPC, of 11,200 and a polydispersity of1.3.

Example 6 (Comparative)

The TEMPO terminated polystyrene produced in Example 5 was heated withcarbon black in toluene under an inert argon atmosphere, and under theconditions set forth in the Table below. The resultant carbon black wasextracted with tetrahydrofuran to remove unattached polymer, and theresidual polymer attached to carbon particle was determined by TGAanalysis.

Carbon Black Polystyrene Polymer Amount Amount Temperature TimeAttachment by (by weight) (by weight) (° C.) (hours) TGA (by weight) 10%90% 140 44 9.4% 50% 50% 125 23 6.2%

Example 7

Ethylaniline Carbon Black Adduct 1

To a suspension of ethylaniline (4 mmol) in water (60 mL) was addedhydrochloric acid (37%, 8.0 mmol) and Vulcan® 7H carbon black (10 g). Asolution of sodium nitrite (4.4 mmol) in water (5 mL) was added slowlyand the solution stirred under air for 30 min. The temperature wasincreased to 70° C. and stirring continued for 3.5 h. The solution wasfiltered and washed with water (4×100 mL) and dried in a vacuum oven for24 h.

Tempo Carbon Black Adduct 2

The modified carbon black 1 (50 g, 0.4 mmol/g, 20 mmol) was purged withN₂ for 30 min, followed by addition of toluene (250 mL), and TEMPO (40mmol)., t-Butylperoxide (100 mmol) was added dropwise and the solutionheated at 100° C. for 48h. Methanol (100 mL) was added, and the modifiedcarbon black removed by filtration, followed by washing with methanolinto the washings were colorless (4×200 mL).

Poly(chloromethylstyrene) Modified Carbon Black 3

The modified carbon black 2 (10 g, 4 mmol) was purged with N₂ for 30min., followed by addition of toluene (50 mL) and chloromethylstyrene(40 mmol). The solution was heated at 130° C. for 72 h with stirringunder nitrogen. Methanol (50 mL) was added and the solution filtered.The residue was washed with methanol until the washings were colorless(4×100 mL). An additional soxhlet extraction was conducted for 72h onsamples intended for analysis.

While ethyl aniline was diazotized onto carbon black, this method isequally applicable to other particle surfaces where an alkyl group orother group containing an abstractable proton is available or able to beapplied by chemical reaction. By-products of this reaction are limitedto t-butanol and unreacted TEMPO, allowing facile purification andrecycling of products and reagents. This method may be utilized for theabstraction of a proton from an alkyl group or other group by anyperoxide. The material formed may then either be employed as a initiatorfor “living” free radical polymerizations by addition of a monomer, orpurified by precipitation and/or extraction before reacting with amonomer. Reaction of the TEMPO adduct under standard TEMPO “living freeradical polymerization conditions results in the formation of a polymer,as analyzed by elemental analysis and TGA. This method may be utilizedto polymerize any reactive monomer known to react under “living” freeradical polymerization conditions. In addition to the cost benefits thatthis method provides, it also provides a cleaner route to industrialscale polymer modified particles.

Other embodiments of the present invention will be apparent to thoseskilled in the art from consideration of the specification and practiceof the invention disclosed herein. It is intended that the specificationand examples be considered as exemplary only, with a true scope andspirit of the invention being indicated by the following claims.

What is claimed is:
 1. A method of making a modified particle comprisinga particle having attached a group having the formula:

wherein Ar represents an aromatic group; R¹ represents a bond, anarylene group, an alkylene group,

wherein R⁴ is an alkyl or alkylene group or an aryl or arylene group; R²and R³, which can be the same or different, represent hydrogen, an alkylgroup, an aryl group, —OR⁵, —NHR⁵, —NR⁵R⁵, or —SR⁵, wherein R⁵, which isthe same or different, represents an alkyl group or an aryl group; andSFR represents a stable free radical, wherein said method comprisesreacting a) a particle having attached an aromatic group with a groupcontaining an abstractable proton and which leaves behind acarbon-centered radical when the proton is abstracted with b) a reactivefree radical source and c) a stable free radical source.
 2. The methodof claim 1, wherein said SFR has the formula:

wherein R⁶ and R⁷, which can be the same or different, represent asubstituted or unsubstituted alkyl or cycloalkyl group; and Ar²represents an aromatic group.
 3. The method of claim 1, wherein saidparticle is a carbon product, a metal oxide, a metal hydroxide, ormixtures thereof.
 4. The method of claim 1, wherein said particle isgraphite, vitreous carbon, activated charcoal, carbon fiber, activatedcarbon, or mixtures thereof.
 5. The method of claim 1, wherein saidparticle is carbon black.
 6. The method of claim 1, wherein saidparticle is an aggregate comprising a silicon-containing species phaseand a carbon phase.
 7. The method of claim 1, wherein said particle isan aggregate comprising a metal-containing species phase and a carbonphase.
 8. The method of claim 1, wherein said stable free radical sourceis 2,2,5,5-tetramethyl-1-pyrrolidinyloxy,2,2,6,6-tetramethyl-1-piperindinyloxy, or derivatives thereof.
 9. Themethod of claim 1, wherein said reactive free radical source comprisesorganic peroxides or azo initiators.
 10. The method of claim 1, whereinsaid reactive free radical source is a benzoyl peroxide or a t-butylperoxide.
 11. The method of claim 1, wherein said reactive free radicalsource comprises t-butyl peroxide.
 12. The method of claim 1, whereinsaid group which contains an abstractable proton and is capable ofleaving behind a carbon-centered radical upon proton abstractioncomprises an alkyl group or an alkene group with a hydrogen atom in thealpha position to the olefinic bond.
 13. The method of claim 1, whereinsaid group which contains an abstractable proton and is capable ofleaving behind a carbon-centered radical comprises a C₁-C₂₀ alkyl group.14. The method of claim 13, wherein said C₁-C₂₀ alkyl group is a methyl,ethyl, propyl, butyl, or hexyl group.
 15. The method of claim 13,wherein said C₁-C₂₀ alkyl group is an ethyl group.
 16. The method ofclaim 1, wherein said aromatic group is first attached onto the particleand then said group containing an abstractable proton which leavesbehind a carbon-centered radical upon proton abstraction is thenattached onto the aromatic group.
 17. The method of claim 1, wherein anaromatic group having attached thereto a group containing anabstractable proton which is capable of leaving behind a carbon-centeredradical is first formed and then attached onto the particle wherein saidaromatic group is directly attached to the particle.
 18. The method ofclaim 1, wherein R¹ is a bond, R² is hydrogen, R³ is an alkyl group SFRis 2,2,6,6-tetramethyl-1-piperindinyloxy, and said particle is a carbonproduct.